Do Christians have to marry in churches? Historically, many Christian theologians have said “yes.” But they haven’t always. It wasn’t until the tenth century, for example, that the Byzantine emperor made a church ceremony a required element of marriage for Orthodox Christians. Nor was Constantinople at the forefront of the matter. A much earlier example, perhaps the earliest, of a churchman saying definitively that marriage isn’t marriage without a specific Christian ritual comes from an unexpected corner of the late antique world: the Persian Gulf island of Dayrin (modern Tarut in Saudi Arabia) under the rule of the early Muslim caliphate. On this island in 676, Patriarch George I—chief bishop of the Church of the East, one of the two main churches of the Syriac Christian tradition—issued a canon that only unions that received a priestly blessing would be recognized as legitimate, lawful marriage. George, a monk-turned-bishop from provincial Iraq, preceded the decision in New Rome by three hundred years.

The decidedly Middle Eastern location of this development might appear anomalous in light of the common association between Christianity and the Roman world. But it’s an instructive illustration of how the emergence of Islam, even as it put an end to Christian political dominion throughout much formerly Roman territory, amplified rather than ended significant trends in late antique religiosity. Furthermore, George’s marriage canon exemplifies how ostensibly marginal source materials—in this case, a short Syriac text, not Greek or Latin, produced on a sparsely populated and obscure island—can enliven the study of the late antique world. Landmark transformations in religious traditions rarely spring fully formed from the pages of systematic treatises. They are often cobbled together in settings of conflict or crisis, not unlike the early Islamic Persian Gulf region to which George found himself traveling in 676.

By the seventh century, that region boasted a markedly robust Christian pedigree. Christianity had found its way to East Arabia’s Persian Gulf coast along with the nearby islands in the fifth century at the latest. Among a diverse population of Arabs and Persians as well as Indians who had migrated to the region along the Indian Ocean sea routes, local communities had adopted the Syriac Christianity of the Church of the East. Headquartered in Seleucia-Ctesiphon, the capital of the Sasanian Persian Empire not far from modern Baghdad, the Church of the East provided theological doctrines and an ecclesiastical identity for Persian Gulf Christianity. But this relationship was not a one-way street. In the seventh century, the Persian Gulf region was home to several bishoprics and a network of prominent, flourishing monasteries. Several locals, like Isaac of Nineveh, became influential authors throughout the world of Syriac Christianity. The archaeological remains of East Arabia’s late antique Christians are still being discovered in modern Qatar, Kuwait, and the United Arab Emirates.

In the second half of the seventh century, Muslim rule affected the region’s social and religious landscape in a manner that looked to Patriarch George like an unending crisis. East Arabia had been incorporated into the expanding Arab-Muslim polity in the 630s. During the following decades, the local bishops proclaimed their independence from the Church of the East’s patriarchate in Seleucia-Ctesiphon, likely because the patriarchate’s former Sasanian Persian patrons were no longer in power. Some Christians in the region began to adopt the religion of their new Muslim rulers, with whom many East Arabians shared an everyday language and other cultural affinities. Converting also offered the distinctly material benefit of avoiding taxes, according to one obviously unhappy and disapproving bishop. Other forms of interreligious social contact appear to have been prevalent in East Arabia as well. Patriarch George’s writings suggest that East Arabian Christians habitually drank at Jewish taverns and participated in “pagan” funerals—pagan, that is, in their “un-Christian” ostentatiousness. Significantly, interreligious mixing extended into family relations too. George complains of Christian women marrying “pagans,” here meaning Muslims; he decries Christian men who take multiple wives and concubines. These polygamous practices were likely well established in the Persian Gulf region but were now sanctioned by Islam within certain limits, and thus looked newly attractive to local men.

We know from archaeology that Syriac Christianity in East Arabia persisted into the ninth century. From Patriarch George’s perspective in the late seventh, however, the local church appeared in total disarray. Not only was the region home to apostates, rebellious bishops, and dissolute laypeople, but marriage as locally practiced fell far below his standards. This was of particular concern because marriage was a divinely sanctioned institution, enjoined by God in the Bible and vested with great theological meaning. It made sex licit and thus allowed for the orderly reproduction of humanity in accordance with God’s plan. To Patriarch George, therefore, the East Arabians’ polygamy and interreligious marriages threw a monkey wrench into the gears of a well-functioning Christian society. His solution was to claim a new, exclusive authority for Christian law and its ecclesiastical custodians to bestow validity upon marriage, ensuring clerical oversight and restoring proper order to the institution. He did so at a church synod, held in 676 on Dayrin, that aimed to reconcile the region’s recalcitrant bishops with the patriarchate and address what George saw as other local problems. The Syriac records of the synod include the canon we’ve been concerned with here: only unions blessed by Christian priests and following a proper ritual script, George proclaimed, would be recognized as legitimate marriages. Whatever arrangements, civil or otherwise, that East Arabian Christians had made before were now out of the picture. Fashioning Persian Gulf Christianity into the form preferred by the Church of the East’s patriarchal center thus meant extending a newly authoritative ecclesiastical law into the household—and devising a novel notion of canonical Christian marriage.

Notably, this notion did not emerge from the late antique Christian heartlands of Constantinople, Antioch, or Alexandria. It is found instead in a set of Syriac canons issued by a little-known bishop in a fairly marginal corner of the Muslim caliphate. Yet it is all the more instructive for that fact. George’s definition of valid Christian marriage responded to a specific Arabian context in which early Islam had introduced new religious identities and allowed for practices that challenged ecclesiastical notions of societal order. The principle that only a priest’s blessing could create the bond of marriage was made explicit at a time of conflict and in opposition to other, equally imaginable possibilities. Like so many other familiar religious institutions, this form of canonical Christian marriage was not primordial; creative human agents claimed it as normative at a particular historical moment.

In his decision, Patriarch George exemplifies the possibilities that yet remain for exploring late antique history from seemingly peripheral vantage points. Most historians would now agree that the emergence of Islam marked not the end of the ancient world but the continuation and, in some cases, the intensification of late antique patterns in politics, religion, and society. The fusion of empire with a universalizing monotheism is a common example. George’s canon signals a development at once smaller yet just as enduring: the continued elaboration in the Muslim caliphate of a characteristically late antique concern to regulate sexuality and hitch its symbolic power to the religious community. Christian marriage wasn’t invented in the Arabic-speaking, Muslim-ruled Middle East, but that setting was vital to its history.